Vortex threads

In their milestone work, Melander and Hussain found that the method of complex helical wave decomposition was instrumental in modeling both laminar as well as turbulent shear flows associated with coherent vortical structures, and revealed much new important data about this phenomenon than had ever been known before through standard statistical procedures. In particular, this approach plays a crucial role in the description of the resulting intermittent fine-scale structures that accompany the core vortex. Specifically, the large-scale coherent central structure is responsible for organizing nearby fine-scale turbulence into a family of highly polarized vortex threads spun azimuthally around the coherent structure. 

Fiq>9 Bubble creneration in vortex threads in the wake of a turbine stirrer (6). 

Fig. 7.11 Wake configurations for drops in water (highly purified systems), reproduced from Winnikow and Chao (W8) with permission, (a) nonoscillating nitrobenzene drop = 0.280 cm, Re = 515 steady thread-like laminar wake (b) nonoscillating m-nitrotoluene drop 4 = 0.380 cm. Re = 688 steady thread accompanied by attached toroidal vortex wake (c) oscillating nitrobenzene drop 4 = 0.380 cm. Re = 686 central thread plus axisymmetric outer vortex sheet rolled inward to give inverted bottle shape of wake (d) oscillating nitrobenzene drop = 0.454 cm. Re = 775 vortex sheet in c has broken down to form vortex rings (e) oscillating nitrobenzene drop d = 0.490 cm. Re = 804 vortex rings in d now shed asymmetrically and the drop exhibits a rocking motion.

The nonnal threads are called vortices or fluxoids. The currents act so as to repel each other, so that the flux lines form an ordered structure called a fluxon lattice, flux lattice or vortex lattice. At the core of each flux vortex the material is effectively normal, but is surrounded by a region of superconductor. 

The planning of the device and pipe connections as well as of the assembly and electric connection of the measuring devices require so-called mechanical measurement setups (hook ups). In Figures 4.21 and 4.22 the hook ups are shown in an example of an analogous flow metering (vortex principle) and a D4 threaded... 

Figure 18.33 shows the vortex structure of the wake at Re = 250 from different side views. The presence of a plane of symmetry in the flow is obvious in the first two pictures. The synunetiy plane nearly coincides with the (z, x)-plane. The release of fluid in two separate tails is clearly evident and obviously corresponds to the double-thread wake observed by Magarvy and Bishop [37] for 210 free-stream fluid is entrained from the positive-z side. 

Researches on studying of separation properties were spent on metal dual-lead vortex tube Z)=125-2.5mm with a diameter on a thread of 175mm with a variable depth of thread from 10 to 25mmwatercolumn of cutting of 8.5, a conditional outlet angle of gas a =78°. Superposition of ultrasonic vibrations for clearing of a gas mix was spent with the following fasted frequency 18.5 21.6 22.1 23.5 kc. The best results are had at frequency of ultrasoimd 21.6 kc. 

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